Antibody productionImmunity and vaccination

Monoclonal antibodiesBlood clotting

IB2 BiologyJin Young

Stages in Antibody Production

1. Antigen presentation2. Activation of helper T-cells3. Activation of B-cells4. Production of plasma cells5. Production of memory cells

Stage 1: Antigen presentation

1. Macrophages take in antigens2. Attach to MHC proteins3. Move to the plasma membrane4. Antigens displayed on the surface

Stage 2: Activation of helper T-cells

Receptors with same antigen-binding domain

1. Helper T-cell binds to macrophage2. Macrophage activates T-cell

Stage 3: Activation of B-cells

1. Inactive B-cells with antibodies in plasma membrane

2. When they match an antigen, they bind

3. Activated helper T-cell bind to B-cell4. B-cell is activated

Stage 4: Production of plasma cells

1. Activated B-cells go through mitosis• Cloning

2. Become active3. Develop plasma cells (cytoplasm)4. Synthesis of large amounts of

antibody

Stage 5: Production of memory cells

T-cells and B-cellsRemain and rapidly respondGive long-term immunity

Animation

http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter14/animation__t-cell_dependent_antigens__quiz_1_.html

Active and passive immunity

Active immunity: antibodies by the organism itselfPassive immunity: antibodies received from another organism During pregnancy antibodies passed to

the fetus

Vaccination

Vaccine Weakened forms Killed forms Chemicals produced by the

microorganism

Booster shot Stimulate production of enough

antibodies

Vaccination (contd.)

Benefits Epidemics and

pandemics prevented

Deaths prevented Disability prevented

Reduce health care costs

Dangers Adverse reactions

Severe allergic reactions (anaphylaxis)

Fever Pain Swelling redness

Principles of antibody production

Clonal selection > 1015 antibodies B-cells clone themselves

Challenge and response Immunity developed only when disease

challenges the immune system

Production of monoclonal antibodies

1. Antigens injected to an animal2. B-cells extracted from the animal3. Tumour cells obtained4. B-cells fused with tumour cells5. Hybridoma cells- produce antibody6. Antibodies are extracted and purified

http://highered.mcgraw-hill.com/olc/dl/120110/micro43.swf

Blood clotting

Blood clot: semi-solid from blood Seal up the wound Prevent pathogens entering

Platelets: small cell fragments that circulate in blood plasma

Clotting

1. Release of clotting factors• Damaged tissues• Plasma

2. Set off a series of reactions

3. In the last reaction, soluble plasma is altered

4. Long proten fibres, fibrin5. Fibrin forms a mesh of fibres, incld. blood

cells

6. Form semi-solid clot

7. Dries when exposed to air

Vocab

Antigens: foreign proteins that trigger an immune responseAntibodies: protein molecules that we produce in response to a specific type of pathogenMacrophage: a type of leucocyte that gets involved very early in the process of fighting off a pathogenFibrin: fibrous protein which forms a mesh-like network that helps to stabilize the platelet plug

Active immunity: the organism produces antibodies on its own; always leads to the production of memory cells and thus provides a long-term immunity to a pathogenPassive immunity: when one organism acquires antibodies which were produced in another organism